Fifteen
by tanteigirl
Summary: Conan stopped forgetting his birthday. If it was because of growing up again or having the magician in his life, he didn't know. Sometimes it made it all more difficult to be close, though. KidConan/KaiConan/KaiShin. Might or might not end up as a one-shot.


_**Title:** Fifteen_

_**Summary:** Conan stopped forgetting his birthdays. If it was because of growing up again or having the magician in his life, he didn't know._

_**Words:** 3179  
_

_**Warning:** Underage drinking and suggestive themes._

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_-Nineteen_

On the first birthday he celebrated with the thief, he would be turning nineteen but instead appeared _nine_. The party had been crazy boisterous with all the Shounen Tantei Dan running around in Hakase's place and Ran chatting animatedly with every guest about how big he was already. Yeah, right. His Osakan friend didn't miss it either, contributing greatly to the noisy atmosphere, as he remained hard to shut up as always. Everything had come to an end, fortunately, and he found himself escaping to the backyard searching for some tranquility.

He hadn't expected the figure in white to be there, but something told him the other was indeed waiting for him.

"Good evening, Shinichi," he offered with a smile. He was the only person he allowed to call him that way. He didn't know why himself, but, sometime after forming an alliance and working together, the bond between them strengthened and he believed the magician was special to him.

Conan gave him a tired smile in return and approached the other. He was somehow really happy to see his friend. It was a really awkward moment when KID rested his knees against the green, fresh grass and hugged him, but when he finally fought back the urge to start laughing, he hugged him back.

"Happy birthday, Shinichi."

_-Twenty_

It was five to twelve before a new day began when Conan heard the faintly knocking on his room at the Mouri household's window. He tried to ignore the annoying sound at first, thinking it would be a bird, but the knocking just became louder. He walked over to the source of the noise dragging his feet. He couldn't help the laugh that escaped his throat at the sight of Kaito balancing his body on the frame of the window, which he then opened.

"Was it that difficult to unlock?" he asked with a mocking tone to his friend.

"Oh, don't misunderstand. I was just trying to respect your privacy." He replied with a wicked smile. Privacy? This had to be a first. "Come on Shin-chan, it's almost time," he offered with a smile. He looked fresh, with his unraveling hair in the wind, black hoody and fashionable jeans.

What was the magician trying to do? The detective looked suspiciously at him.

"You didn't forget it, did you?" Kaito asked with a mocking grin.

"I didn't." The boy tried to look offended, but, well, he couldn't say he hadn't forgotten before…

"Then let's go, Shin-chan!"

The detective scolded at the nickname and put on a doubtful face for a second, though he wasn't fooling anyone. He rolled his eyes at the thief, admitting defeat. "Just let me grab my… oh." He took his own dark-gray coat, which had materialized itself in a cloud of white smoke, and took the magician's hand to climb out of his bedroom.

Moments later, they found themselves sitting on the rooftop, watching the most incredible display of fireworks he had ever seen. Every colour and shape was there, which included KID's doodles, detective related things such as Sherlock Holmes' hats and what _really_ looked disturbingly like a corpse. Although it was kind of chilly, the night was great and the boy was enjoying himself greatly.

"Now, for the most important part," the magician said as he handed Conan a little shot glass and made a bottle of sake appear between his hands, "let's drink."

Conan did a double take as he couldn't believe someone was trying to give him, a physically ten year old boy, a cup of sake.

"Shin-chan, you are turning twenty. This has to be done," he insisted seriously. Conan couldn't contain his laughter anymore, but took the glass in his hands nonetheless. He believed the thief used to forget that he was a child more often than him, but just looking at the paralyzing indigo orbs directed straight at him, he thought Kaito could convince him of _anything_.

They clashed their full cups with their eyes locked on each other again. Shinichi felt intimidated, noticing his own cheeks burning hot. What was happening to him?

"Happy birthday, Shinichi," his friend offered in a soft voice that didn't exactly help with his current state.

He drank the entire liquid in one shot, trying to distract himself from his newly formed thoughts. He couldn't remember anything more from that night. He passed out.

_-Twenty-one_

Depression found him first before any party or crazy young man trying to make his everyday life more unordinary than it already was. Conan found himself crumpled on a couch in the living room of his old house. He was considerably taller compared to the six year old boy who had shown up at first; his fingers were longer, his face larger and his body suffered other subtle changes he seemed to be the only one noticing. He was growing again… as Conan. He was furious with himself for not being able to do anything. With no more Black Organization to chase, the race was only against time and he was losing. He was sinking into his acquired identity, slowly but certainly.

It took him several minutes to notice he wasn't the only person in the room. And the other one wasn't even trying to be inconspicuous! He was all dressed in white, for God's sake! KID's face wasn't happy as he observed the little figure crouched on the sofa, his blue hopeless eyes lost in thought. Whatever was going on in his mind, the Moonlight magician wanted to erase it, to cut it from the roots. He wanted to take the other_ young man_ in his arms and place kisses in his forehead. He wanted to tell him everything was going to be alright. He didn't dare, though.

"Tsk, tsk. So mean of you to miss our appointments, Tantei-kun. I had something special planned for you tonight," he spoke with the silky, challenging voice that belonged to Kaitou KID.

Shinichi didn't bother glaring or even looking at him. He got up from his place slowly and started walking away from him, showing him his back. "I don't want to play tonight. Just… leave."

The thief couldn't have that, could he? "I'm afraid I can't do that, Tantei-kun. There's this rule, which only applies to you though, that says: If you don't come to the heist, _the heist comes to you_."

Conan froze on his feet at the malicious voice behind him, and shivered. Something was telling him he wasn't going to be left alone as he intended to go through the night. And when it clicked, he started running for it, climbing the stairs as fast as he could. He wasn't going to win, though. The detective started coughing as a dense smoke surrounded him and then, it happened. A thick substance fell over him, bathing him from head to toes. He started shaking with anger, not being able to believe what had just happened to him and the only thing that crossed his mind was _kill him_. He used his hands to remove whatever was all over him from his face. Looking down at himself, he realized he was sparkling, as he was covered in bright purple glitter mixed with glue.

He turned around slowly with a face that made KID prepare himself to fly any second, and then, started laughing his head off. The magician followed him afterward, and it took five whole minutes to calm themselves down. Kaito didn't know when he had started moving, but when he came to himself, he was just one step below Conan. With the addition of the tread, the boy was less than fifteen centimeters away from his own height. When had he grown up so much? He couldn't help himself as he moved closer to the surprised pre-adolescent and placed a chaste kiss on his cheek.

"Happy birthday, Shinichi."

_-Twenty-two_

On his twenty-second birthday, Conan encountered Kaito running up to him in the airport. The young man grabbed him and put his arms around him, reluctant to let him go. He didn't speak a word as the younger boy latched his body to his own, and he shuddered when he felt fingers interlacing with the hair of his nape. He took a deep breath from the crook of the detective's neck, and his own hands travelled everywhere on the growing boy's back. "I'm sorry," the broken voice reached his ears and he didn't want to let go, but he knew he couldn't do anything that'd make his friend stay. "I have to go now." Conan had his head against the magician's chest, listening to the fervent heartbeats. He thought to himself that it had to be the sweetest sound ever.

"Happy birthday, Shinichi," Kaito whispered, but the shake of the boy's head didn't go unnoticed.

"From now on I'm Conan." he responded sadly. His eyes were watery, and he felt like he could break down any minute.

Kaito let go of him to look at his deep, blue eyes with the most serious expression he could muster. "You _really_ don't expect me to think that, do you?"

The detective smiled softly at the young man in front of him and felt the sudden urge to grab onto him and hear him say "Stay"; maybe this time he'd comply. He put his hands on his own face and grunted, sad and confused.

"What's wrong?" his friend asked as he took the boy's hands between his own, and it was stupid really, because so many things were _wrong_.

Conan's eyes were tired, glassy and resigned when he answered, "I'm _twelve_."

The only thing Kaito could do was squeeze his friend's hand slightly and watch him go.

_-Thirteen_

Conan dropped himself on the queen sized bed. Over his visit, Kaito had ended up talking more to his parents than to him, which made him furious. He was sure his friend had noticed, and that had only made things worse. He had to lock himself up in his bedroom several times a day trying to escape the circus. He understood when they were talking about Toichi-san, but sometimes the conversation diverted and was too much for him to handle. Fortunately, they had abused too much conversation where his mother asked Kaito whether he was dating someone and offered herself for the position. Lamely, they had moved on to make him the central topic of their chats, and he feared they weren't going to stop any time soon.

He growled against the pillow and tried to bury his embarrassment and jealousy.

"Shinichi," he heard from the door, "I'm going to come in." Really, why did he even bother locking it?

Soft steps stopped next to him and he could feel the magician's hesitant breath before he jumped onto the bed to his side. "Don't be mad, we're just joking _most_ of the time." His laughter echoed in the room and the younger boy felt shivers down his spine. One week ago, this man was so out of reach and now, he was lying next to him on his own bed. "Though I fear your mother was quite enthusiastic about looking for a wedding dress for you." The detective's growl was muffled by the sheets and the thief laughed sweetly again. "Tomorrow's my last day here. Come on, don't be mad at me, Shin-chan."

The younger boy felt a pang in his heart when he remembered he was going to be separated from his friend again. He didn't want him to leave, but there was nothing he could do. The magician had to attend University and continue with his shows and heists. He offered a sad "okay," but because of his bad mood he couldn't take his head from the pillow.

Kaito's soft touch wandered from his head to his back, and he melted at the caresses. He tried not to twitch every time he was touched in a sensitive place. There was a limit to every teenage boy though. He wanted to be swallowed by the mattress as an "ahh" escaped his lips when he couldn't bear it anymore as the expert fingers brushed slightly against his neck. He froze as Kaito's ministrations stopped altogether. Some seconds passed and he didn't say a word, so he was utterly surprised as strong arms flipped him over.

The detective looked up, breathing heavily through parted lips, to notice how Kaito's pupils grew wider to reflect him. His whole body trembled at the wave of heat running through him. The tingling lasted longer in those parts of his body he was eager for the magician to touch. He contained his breath as the young man above him started coming closer and he licked his lips expectantly, only to be interrupted by an alarm going off.

It was unfair to leave the detective like that, but the ringing sound made Kaito come out from his stupor, and he let himself fall on the mattress next to the detective. His whole body was burning and he suspected the other boy felt the same. He wanted to do something, anything. It was just that…

"Happy thirteenth, Shinichi," he managed to say. He searched for the smaller hand and squeezed it lovingly, not daring to move an inch from where he lied.

It was Conan who stood up from the bed moments after, and Kaito wished he hadn't asked where he was going.

"Bathroom!" he screamed back at him, and he didn't sound happy at all.

_-Fourteen_

When Kaito opened the door, he found a fourteen year old teenager standing with a suitcase in front of his apartment, wearing a smile only made for him. He laughed as the teen whispered, "I can't believe I'm doing this", but didn't care and he closed the gap between them and took the teenager between his arms. "You're late. The cake's gone bad," he offered back and Conan scoffed. "You realize how hard you made it for me to come back to Japan unnoticed after your last _show_, don't you?"

Kaito smiled wickedly in return, "that's how much I missed you." The detective went red at the sudden declaration. He was definitely not accustomed to the cheesy talk, but he also was really happy to hear that. He felt the same. His tongue stuck in his throat though, and he could only answer with a reassuring smile.

It was only when he was inside and Kaito closed the door behind him that he stopped to look at the young man appropriately. He was taller than the thief he had met several years ago. And although he kept the slim figure, his back was slightly wider, and his toned arm muscles were considerably evident through the thin fabric of his shirt. The detective wondered if he could still impersonate women; he concluded that he couldn't, at least not in summer.

Even though he was reaching 160 centimeters already, he was quite small compared to the young man next to him. He tried to stop himself as he thought the other would be able to do _everything_ he wanted with him, and he wouldn't stand a chance trying to oppose him. Ha, as if that was going to happen. He wondered how much force it would take for his friend to _break_ him.

_Stop._

He felt his face burning hot and tried to look away but he couldn't. Not with the way Kaito was looking at him, with that wicked grin plastered on his face and making him believe that he could read his mind.

They didn't stop for ceremonies as the thief came to him and grabbed him by the waist and brought him to his body, using a free hand to caress him strongly between the ear and the neck. The boy melted to the touch before Kaito couldn't stand it anymore and dug in, waiting for their lips to clash together before kissing him passionately. The kiss was hot and wet, and only then they realized how desperate they were for each other. _Perfection_ could only describe their tongues entangling with each other, making a mess of their hair, pressing together their bodies together even _more_.

It was a long time until they separated their lips, and the detective rested his head against the magician's shoulder. Kaito put his cheek on the boy's head, as his strong hands continuously drew patterns on the smaller back.

"I came to stay", Conan spoke expectantly into the young man's arms.

"Good. I wouldn't have let you go anyway." The teenager let out a breath he didn't know he was holding in and smiled happily.

"Belated happy birthday, Shinichi."

_-Fifteen_

The clock announced twelve in the morning as Kaito sat on the living room's sofa. The immense balcony window was slightly opened, and a refreshing, cold breeze found its way inside. The full moon was up in the sky, and moonlight fell on the magician's slim figure. He accommodated himself further in his seat as he juggled some toys, stuff he had found around the house really, wondering if he should wake Shinichi up or let him sleep. He would be seeing him once come morning anyways.

He definitely wasn't expecting to see said detective walking up to him wearing seemingly nothing more than an overlarge t-shirt. He gulped as his sight stopped on bare. thin legs, and he almost let the toys fall to the mushy carpet that covered the floor. He silently stopped his activities and watched as his friend, roommate, boyfriend approached him with slow, but decided, steps. _You're going to be the death of me, Shin-chan._

He tried not to touch as the other stopped before him, but couldn't. He placed a hand on the teen's hip, squeezing lightly, and earning the reaction he wanted as Conan's sensitive body stirred under his fingers. He wasn't thinking straight as those beautiful legs straddled him, the detective taking place on his lap as if he belonged there. Kaito thought the other did. Trying not to lose it, he shook his head slightly and raised a hand to delicately touch the other's left cheek.

"Happy birthday, Shinichi," he said, trying to sound as calm as he could. He wanted to possess this young man. He wanted to make him cry and bend over in pleasure. He wanted to kiss every inch of his body. The wait had been too long, and he could hardly bear it. If the detective didn't leave that instant, maybe he was going to start something he wasn't sure he could stop.

But the younger man was serious and his eyes penetrated deeply, and the only thing Kaito could think was _closer, closer, closer. _He was looking at him seductively as his hands started roaming his chest, his neck. They entangled with his hair and he moved his hips just slightly, although the magician wasn't sure if that had been on purpose. He was on the edge nonetheless. The detective leaned toward his ear before whispering, "I think fifteen is grown up enough".

Kaito couldn't agree more.

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_Happy 2014 for everyone!_

_Thanks to Madame of all Manga for having beta'ed this._

_Are you curious to know what show Kaito did when Shin-chan was out of the country? That might call for an omake~ _

_Hope you enjoyed and please review!_


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